High‐resolution XPS spectromicroscopy

Abstract

The field of XPS imaging and spectromicroscopy has recently made significant progress thanks to laboratory X-ray photoelectron emission microscopy (XPEEM), a novel, versatile parallel imaging method for which lateral resolution of core-level images in the 500 nm range, and spectromicroscopy from decanometric-size area of interest have been demonstrated (J. Electron Spectroc. Relat. Phenom. 171 (2009), 68). It uses a bright microfocussed monochromated Al Kα source and a photoelectron emission microscope (PEEM) as entrance lens of a high-transmission, aberration-compensated imaging spectrometer in the form of a double hemispherical analyzer. In this paper, restricted to laboratory aspects of XPS spectromicroscopy, we will first give some details of this novel instrumentation after a short historical review of the field until the presently existing imaging techniques. Then, some of the first results of laboratory core-level XPEEM on practical samples will be presented. Future perspectives towards quantitative analysis, improvements of lateral resolution and multitechnique spectromicroscopic aspects with laboratory sources (including UPS spectromicroscopy in direct and reciprocal space) will be drawn.

Chemistry and electronics of single layer MoS2 domains from photoelectron spectromicroscopy using laboratory excitation sources

“…In this context, advanced highly resolved XPS imaging methods, also able to provide a comprehensive set of information, are needed. X-ray PhotoElectron Emission Microscopy (XPEEM) [5][6][7] is a powerful tool to study 2D-TMDs [8] because it provides access to spectroscopic information with high-energy (<0.5 eV), lateral (<0.5 μm to 1μm in routine analysis [9,10] ) and wave-vector (<0.1 Å À1 ) resolutions. XPEEM therefore goes far beyond the capabilities of current XPS microscopes because very high lateral resolutions in core-level imaging are reached and complementary work function mapping and valence band structure imaging can be performed.…”

Principal component analysis: Reveal camouflaged information in x-ray absorption spectroscopy photoemission electron microscopy of complex thin oxide films

“…Tutorial description of PCA applied to XAS (x-ray absorption spectroscopy) and EXAFS studies were published a couple of years later by Wasserman et al [13,14]. Multivariate techniques with compositional and lateral resolution were applied to PEEM studies of Ge oxide surfaces [15][16][17]. Ag, Ni, Ti metallization layers [18] and Au-Sn surfaces [19] were studied using PCA by Walton et al and Renault et al.…”

Imaging XPS for industrial applications

“…Of notable mention here are photoemission electron microscopy (PEEM) systems, such as the NanoESCA from Omicron. Such systems yield an unparalleled lateral resolution of 650 nm (0.65 µm) in a standard laboratory environment, although the high electric field generated between the sample and the cathode lens system used, limits the use for insulating samples [13][14][15].…”